The invention relates to an apparatus for delaying the pressure drop in a pressurized cabin or the like in an emergency. Such pressure drop may, for example, occur in an aircraft body when a door locking mecanisme or seal fails in flight. Heretofore, such failures of the door seal made it practically unavoidable that the pressure equalization took place instantaneously. However, it is important that in such emergencies the pressure inside the cabin or aircraft body is not instantaneously adapted to the pressure outside the cabin. The resulting damage might cause crash landings. Therefore, it is desirable that the pressure equalization is delayed as much as possible.
Thus, especially in passenger aircraft, efforts are being made to construct the doors in a highly reliable manner. Thus, it is known to take advantage of the pressure inside an aircraft cabin for pressing the doors during flight against the holding hardware forming part of the aircraft body. Freeing the door from such holding means may be accomplished by lifting, lowering, or laterally shifting the door. This type of door closure assures a relatively high reliability, especially in combination with effective locking and control devices, however, the costs are rather high.
However, in larger aircrafts, especially in freight type aircrafts, the space required for the above type of door structure prevents its use because the available space must be used in an economical manner. Freight space doors are quite frequently hinged about a horizontal axis arranged in the area of the upper door edge. The door structure is such, that in the closed condition the door is interlocked with the surrounding aircraft body structure so that the door is capable of taking up the loads resulting from the pressure inside the aircraft body structure. Thus, the safety of such doors depends entirely on the locking mechanism. If the locking mechanism fails for any reason whatsoever, it is possible that the door springs open during the flight.
In modern large volume aircrafts the volume of the aircraft body is divided substantially in half by a floor. Above the floor there is the space for passengers and below the floor there is the freight space. Both spaces are under inner pressure during the flight, whereby a pressure equalization is accomplished through a respective device in the floor. Thus, when, for example, a door of the freight space springs a leak or is lost altogether during the flight, the pressure in the freight space drops abruptly, for example, within 50 msec. The pressure in the passenger cabin or space cannot be equalized with such a rapidity whereby the floor may yield to the pressure inside the passenger cabin thereby breaking. Such destruction of the floor may damage or destroy vital systems, especially system conduits, which in trun may cause the crash of the respective aircraft.